Proteins isolated from animal sources are susceptible to being contaminated with virus particles and/or virus DNA which is unwanted when the proteins are to be used, e.g., in food or pharmaceutical products. Methods are known for purification of such proteins which will also reduce the level of virus particles and/or virus DNA, such as chromatography, filtration, centrifugation, extraction or precipitation. However, in some cases, the purification of a protein of interest is difficult, time-consuming and/or expensive. It is therefore an object of the present invention to provide a method for removing from a protein of interest any contaminating virus particles and/or virus DNA. Such method should be fast, useful in industrial scale, inexpensive and effective.
Trypsin (EC 3.4.21.4) is a serine protease found in the digestive system of many vertebrates where it hydrolyses proteins. Trypsin is available in high quantity in the pancreas of mammals and, e.g., porcine and bovine trypsin can be purified rather easily. Hence, trypsin has been used widely in various biotechnological processes. Further, trypsin is used in baby food to pre-digest the protein.
Porcine circovirus type 2 (PCV2) is a small non-enveloped virus which replicates autonomously in eukaryotic cells. It is the etiological agent of Postweaning Multisystemic Wasting Syndrome (PMWS), a new emerging and multifactorial disease in swine.
It is an object of the present invention to provide a method for removing PCV2 virus particles and/or virus DNA from trypsin extracted from porcine pancreatic glands.